Steering play 124

[5pdrman]

I have a 1978 Fiat 124 and when the car is sitting still, there doesn't seem to be any play in the steering wheel, but when I drive it there is a little left and right steering motion with the wheel before the tires react. Where do I start looking first?

Larry

[lm48]

Mine does the same think. I just had the alignment done and check all the steering component and there is no play.

[5pdrman]

I'm in Naples, who did your work, Hunt?

[kmead]

There are a bunch of factors that could be at play. The first is the connection to the road, often the only tires we can find are of the rim protector variety (as in rubber rings that keep you from getting dents in your rims) which are very soft and don't react very quickly to inputs. After that one gets into the mechanical bits: steering box (which is adjustable), the idler arm, four different tie rod ends, a center link with a connection much like a tie rod end at both ends, ball joints on the upper and lower A arms and finally the wheel bearings (which if they are not grinding or howling are likely fine).

I would start by getting an assistant, they don't need to be particularly skilled as they are going to sit in the drivers seat and wiggle the steering wheel on command.

Now you get to reach under the car to grasp each of the rubber tie rod ends with your thumb and forefinger wrapping them tightly to compress the rubber against the metal parts inside. For each one have your assistant wiggle the steering wheel left to right about an inch. Presuming there is no motion at the first one in the straight ahead position, turn the wheel all the way to the right and perform the same action again on the outer tie rod end and then the inner tie rod end at the steering box Pitman arm. Presuming both are tight and have no relative motion when the steering wheel is wiggled, proceed on to the center link's left end where it attaches to the arm of the steering box, again wiggling and feeling for relative motion.

Now move to the right side of the car and go through the same steps on the right side of the car starting with the wheels pointed straight ahead and then turned all the way left.

After noting and finding any offending parts its time to look at the steering idler mechanism. It is mounted to the right frame rail right behind where the exhaust down pipe sweeps back towards the rear of the car. With the car tires pointed straight ahead, watch the idler arm as your assistant wiggles the steering wheel. If you can see vertical motion of the arm itself the bearings/bushing inside is worn out and the unit will need replacing. There are two versions of this part, a dry bushed version which is the newer version and hydraulic version which can be refilled with oil. One can switch one for the other with no issues. I prefer the hydraulic version.

The steering box is adjustable, the proper way is to remove it to adjust it but no one I know has ever done it the "right way". The non right way which works very well, starts with putting the front end on jack stands. To adjust you need to loosen the lock nut on the steering box and then tighten the jack screw with the slotted end inward to take up the slack between the worm and roller in the box. Loosening the lock nut is the hardest part, as I recall and I may well be wrong, the nut is a 22mm which I have always used a crow foot wrench on it. When you loosen the nut be sure to hold the jack screw so it doesn't move so you don't have to figure out where it should be again to start. You tighten it just a little at a time until there is no apparent motion between the steering wheel moving and the arm at bottom also moving. After each adjustment run the steering wheel from lock to lock to ensure the proper bedding of the parts through their travel. Always return to center before adjusting again.

You don't want to over tighten the steering box as it can make steering very heavy and cause excessive wear in the box.

If you don't have relative motion between the arm and the steering wheel leave well enough alone as you don't want to break something that isn't broken already.

Something you should consider doing is also looking at all of the rear suspension's trailing arms and the Panhard rod's rubber bushes as worn ones can cause rear end to do some steering of its own. Giving the impression that the front isn't really turning in when the rear is actually countering the steering input until the slack in the bushings is taken up. Having all suspension parts front and rear in good shape is key to proper steering, ride and safe handling.

Hope that helps.

Karl

[Weelan]

Wow, a ton of great stuff here. Saving this for a later read, thanks kmead!